Difference between revisions of "SA22C:History"

From Rotary Engine Wiki
Jump to: navigation, search
Line 1: Line 1:
The 10th Anniversary Mazda RX-7. Very Special. Very Scarce
<google uid="C01"></google>
Mazda RX-7
Mazda RX-7
Line 124: Line 124:
* International Motor Sports Association (USA)
* International Motor Sports Association (USA)
The 10th Anniversary Mazda RX-7. Very Special. Very Scarce
<google uid="C01"></google>

Latest revision as of 20:44, 20 May 2012

<google uid="C01"></google>

Mazda RX-7

By Jack Nerad Driving Today

The Mazda RX-7 sports car was the result of a remarkable confluence of disparate antecedents that somehow fell together to create something great. The characters involved in the story are so different, and the twists and turns in the narrative so strange, that you might be tempted not to believe a word of it. Yet, the car with an engine that many proclaimed would never work, built by a company founded to process cork, suddenly became one of the most successful sports models the United States has ever seen. Go figure.

As you no doubt know, Ahura Mazda is the Zoroastran lord of light and creator of the universe. Now to determine how that name related to a failing Japanese company that switched from manufacturing cork flooring products to three-wheeled trucks, you would have to ask Jujiro Matsuda, quite a difficult task, since the son of a Japanese fisherman is long since dead.

Matsuda was born on August 6, 1875, in Hiroshima Prefecture and by the age of 13 with his sea-faring father passed away, he was apprenticed to a blacksmith. Ambitious, he started his own blacksmithy's operation and at one time employed 50 workers, but the vagaries of the turn of the century Japanese economy drove him out of business. Undaunted, he tried to establish more businesses, and finally he invented and patented a newfangled pump, which resulted in the establishment of the successful Matsuda Pump Partnership. His partners in the venture didn't prove too trustworthy, however, and soon he was forced out of his own company.

By this time entrepreneurship was in his blood, and in 1912 he formed Matsuda Works, an armament manufacturer whose major client was the Russian Czar. Ecumenical in his business, he formed another company to build weaponry for the Japanese Army, then he sold out the whole shootin' match to Nihon Steel. Barely 40 years old, he was rich and retired.

When World War I reared its ugly head, one oddball fallout of the hostilities was the impossibility to get good cork in Japan. To remedy this heinous situation, several Japanese investors formed Toyo Cork Kogyo, which processed a Japanese knock-off of cork harvested from Abemaki trees. During the War to End All Wars, this substitute cork seemed acceptable, but when the war ended and Japanese could get real cork again, Toyo Cork Kogyo fell on hard times and the bank that had lent it capital reorganized it-something that would happen at least twice more in its checkered history.

What about Mazda? What about cars? What about the gosh-darn RX-7? Well, who should be brought in to rebuild the desperate Toyo Cork Kogyo? None other than the fisherman's son, Jujiro Matsuda. After becoming president, he quickly pulled the company out of the fake cork business and into industrial manufacturing. In the process, he changed the name of the company to Toyo Kogyo Kaisha Ltd, which is about as generic a name as you can imagine since it means Orient Industry Company, Incorporated. A name like that could make practically anything, and soon it was involved in the manufacture of three-wheeled trucks, its entry into the car business.

To call these vehicles "trucks," though, might be a bit misleading. They were essentially three-wheeled motorcycles with a small cargo area, perfect for hauling goods in the unbelievably narrow Japanese. Equipped with 500 cubic centimeter engines, the Mazda Type DA Tricycle Trucks proved to be popular in both Japan and China in those years between the two great wars.

Today Japan is a hugely successful automotive exporter, but in those days the Japanese motor industry was just this side of a farce. Most motor vehicles were imported, and the relative few that were not were built under license copying American or European designs. So Toyo Kogyo, manufacturing three-wheelers of its own design, was a leader. And with World War II about to explode around it, in 1940 the company even introduced a car prototype, a tiny sedan that bears some resemblance to the current Chrysler PT Cruiser.

World War II destroyed any chance that vehicle might have had for series production. Instead, Toyo Kogyo was pulled into the manufacture of war materiel, and then, ironically, on Matsuda's 70th birthday, it somehow escaped total destruction when the atomic bomb was dropped on Hiroshima.

At the same time, more than halfway around the world, a man whose ups-and-downs roughly paralleled Matsuda's was having a very hard time of his own. Felix Wankel was born on August 13, 1902 in Germany's Black Forest. By the age of 12 he, like Matsuda, lost his father, who was struck down by shrapnel in an early battle in World War I.

Poverty dogged his family through his teens, and though he was obviously bright, he was unable to continue he education much beyond those high school years. His first real job was, oddly enough, in the publishing business, though he had always been interested in things mechanical. In1924, when his job was swept away by a recession he decided to open his own workshop. There he began his lifelong quest to develop and perfect an internal combustion engine that didn't use pistons, but instead a rotor.

His shop provided him with a decent living, but he continued to pursue his dream of building a successful rotary engine. By his calculations, as well as a wide variety of other inventors who were pursuing parallel paths, such an engine should have many advantages over the conventional piston engine, like the smaller size, lighter weight and significantly less complexity. Wankel drew up plans, sought patents and fiddled with prototypes throughout the Thirties. At the same time, he dabbled in German politics, which was a dangerous thing to do in the Nazi regime. About 1935, he was thrown into prison by the Nazis, but after his release, he participated in the German war effort, and at the conclusion of World War II he was imprisoned by the French.

After his second release, he persuaded the German firm NSU to look at his rotary engine research. Teaming with NSU's Walter Froede, he was finally able to build an acceptable rotary engine in 1957, conquering, at least partially, a wide variety of technical challenges that included combustion chamber sealing and lubrication.

Wankel quickly established a consultancy business, and he began to thump the tub for his remarkable new engine. Manufacturers from around the world stopped in for a look-see, one of them was Tsuneji Matsuda, son of Jujiro, who had taken the reins when his father died in 1951. Matsuda feared that the Japanese government was set on a course that would eliminate Toyo Kogyo from automotive manufacturing in the post-war reorganization of the nation's industries, and he thought that building vehicles with the breakthrough engine would buy his company continued independence.

He struck a deal with a reluctant NSU and then waited while the German company failed to provide the promised engines and the promised technology. When the NSU engines finally arrived in Hiroshima, the Mazda engineers were shocked. Instead of a breakthrough, the engine was a nightmare of vibration and combustion chamber leaks that resulted in dismal fuel and oil consumption.

But Mazda committed itself to the new technology. To turn back would have been a profound loss of face that could threaten the existence of the company. In an attempt to salvage the situation, Matsuda turned to stalwart Toyo Kogyo engineer Kenichi Yamamoto to lead the rotary engine project.

Though not thrilled with the assignment, Yamamoto bit the bullet and eventually succeeded where all others, including NSU and Wankel himself, had failed. He and his team built a reliable rotary engine. A key difference from the NSU Wankel designs was the rotor seals, which had always been the bugaboo of the rotary.

Satisfied they were on the right track, Toyo Kogyo engineers dropped their brainchild into a stunning two-seat sports coupe called the Cosmo, which debuted at the 1964 Tokyo Motor Show. It was quickly followed by a production version, but the rotary engine got its biggest boost when Toyo Kogyo decided to install the new power plant in a wide variety of its more mundane vehicles, including the popular Familia. By 1971 Mazda had built 200,000 rotary-powered vehicles, but the bottom fell out when the Gas Crisis hit in 1973-74. Rotary-engine vehicles were maligned for poor fuel economy, and Toyo Kogyo was sent reeling into reorganization. It turned out that it was a piston-engine car, the GLC (Great Little Car), which would revive its fortunes.

Still, Mazda engineers were sold on the rotary engine concept. As the company got back on a reasonably even keel, they launched a new development program that would continue in the footsteps of the Cosmo. Code-named Project X605, the effort would eventually result in the Mazda RX-7. The first prototype was completed in 1977, and in April 1978 the production RX-7 was introduced as a 1979 model.

Led by project head Moriyuki Watanabe, who would eventually ascend to chairman of the board, the Mazda engineers and stylists avoided the trap of the Cosmo. Instead of a complex, extremely expensive car, the RX-7 was designed from the outset to be light, simple and "international." Because of this, Toyo Kogyo was able to price the new vehicle significantly lower than its obvious competition, the Porsche 924 and the Datsun 280Z, and the public on three continents immediately responded to the value.

The car offered a very straightforward hatchback design, bereft of the usual Japanese "surface excitement." Many thought the tapered front end and wide, body-long rubstrip gave it a Teutonic feel. Inside the car was equally no-nonsense with a pair of bucket seats, three-spoke steering wheel and "proper" round gauges. The cargo bay, big for a sports model, was accessible through a large, strut-supported rear hatch.

What the RX-7 didn't offer was just as important to its success as what it did. In the interest of cost savings, Toyo Kogyo engineers specified re-circulating-ball steering, instead of a more-expensive-to-develop rack-and-pinion setup, and they contented themselves with drum brakes on the rear wheels, instead of discs. The same pragmatic approach extended to the suspension. Up front it used MacPerson struts located by lower lateral arms and trailing links plus an anti-roll bar. At the rear, instead of an independent suspension, the RX-7 made do with a live-axle located by four trailing links and a Watt linkage. The rear was sprung with coils, damped by gas-filled tube shocks and fitted with an anti-roll bar.

Of course, the RX-7's key differentiator was under its sleek hood. The engine of choice was a 12A two-rotor displacing a mere 1146 cubic centimeters. In original trim it produced just 100 horsepower at 6,000 rpm and 105 pound-feet of torque at 4,000 rpm, though eventually modifications would bump it up to 135 horsepower. While the power figures aren't impressive, the engine weighed just 312 pounds and the car itself weighed just 2,350 pounds, so its performance was more than adequate.

Though the RX-7 was a hit in Europe, Asia and America, it really struck a chord in the United States where more than 375,000 first-generation cars were sold before it went out of production in 1985. In all, some 500,000 original RX-7's were built, making it, by a huge margin, the best-selling rotary-engine car of all time. And its success fulfilled the wildest dreams of the son of the Japanese fisherman and the son of the German oberlieutenant, whose fates collided nearly a century after their births.



Looking back to 1978, it is almost impossible to believe that the original Mazda RX-7 (codenamed X605) could have been so good. Perhaps it's because true sports cars were thin upon the bitumen in that era. Certainly the assessment has something to do with the essential sportiness of the RX-7 coming as such a contrast to the upright and faintly flabby RX-5 which immediately preceded it. The RX-7 outperformed, outhandled and even out-braked the RX-5. But remember that the newer car was fitted with the 12A rather than the 13B rotary and emerged from Hiroshima with drum brakes on the rear instead of the four-wheel disc arrangement of the RX-5. Within a few years all RX-7s were equipped with disc brakes all round.

Figures alone cannot convey any of the car's charisma, even though a standing 400 metres time in the low 17 second bracket was exciting enough in the Australian context. Consider, for example, that the 4.2 litre V8 Hoiden Commodore could manage a best of 17.4 when equipped with its standard (and primitive, though beefy) four-speed manual transmission. Top speed was about 195 km/h with an even 200 achievable with only a little assistance from wind or gradient. The Commodore, however, was all out by 180 km/h.

To what extent was the RX-7 an RX-3 lurking within a sleeker body? The answer is: very little. Certainly the 12A was still used, as was recirculating ball steering and a disc/drum brake combination. But the development and refinement given to all these components made any resemblance between an RX-7 and a 12A RX-3 faint at best.

Obviously the much lower centre of gravity, the wider track, the far more sophisticated rear suspension, the wider wheels and better tyres combined to transform the overall handling of the car. An RX-3 was average 1970's Japanese sedan in its dynamics, while the RX-7, which was derived from the RX-3, was markedly better than practically any 1979 competitor - whether from Japan, Australia, the US or Europe - and arguably superior to the Porsche 924. But as well as making the rotary sports car agile and balanced, the engineers had built far greater feel and precision into the steering. A broader steering shaft reduced distortion with obvious benefits in the area of steering sensitivity and feel.

In a sense the most remarkable single aspect of the RX-7 was that it was as good as it was despite some quite simple engineering. Along with recirculating ball steering came drum brakes and a live rear axle. Here was a triumph of refinement over revolution, of painstaking attention to detail and of sheer determination to make the first rotary-powered sports car since the original Cosmo, right.

It didn't matter that the rear suspension wasn't independent because it was about the next best thing. The live axle was located by a Watts Linkage. Coil springs, gas-filled Kayaba dampers and an 18 mm roll bar were the other key items. The chassis engineers had chosen the Watts Linkage over a Panhard rod for three main reasons. Firstly, it had been used on factory-sponsored RX-3 racers in Japan. Secondly, it provided a more favourable roll centre. Thirdly, if a Panhard rod had been used the car would have had to be some 75 mm longer.

Dimensionally, the Mazda RX-7 was somewhere between an RX-3 and RX-2 in overall length. At 4285mm, it was somewhat longer than an MGB and significantly bigger than Fiat's X1/9. With a width of 1650mm and a height of just 1260mm and riding on 5.5 inch alloy wheels, the RX-7 had a more crouched, muscular stance than any other Mazda. At 1065kg it was a solid little sports coupe. The cars exported to the US were strict two-seaters but all the RX-7's sold in Australia were equipped with a small folding rear seat like their counterparts on the domestic Japanese market.

From October 1979, all versions of the RX-7 were produced with a superior grade of interior trim, but the big changes came the following year. A revised front end treatment with a combined bumper/air dam arrangement lowered the drag factor to 0.34, which the calculator team at Mazda headquarters equated to five horsepower. Changes to the rear styling ran to neater lights and a tidying up of the number plate housing.

Mechanically, the big news was the fitment of rear disc brakes to the upmarket GSL model (the model sold in Australia), along with superior fuel economy thanks to fitment of a catalytic converter in place of the thermal reactor. A thinner roll bar reduced oversteer through tight corners taken with too much speed and Bridgestone's grippier RD204 radials replaced the previous RD116s.

In Australia the upgraded new version was known as the Series II. This immediately made the previous car the Series 1, even though no manufacturer has ever officially called a new car the Series 1. October 1983 brought the P132 series. US buyers scored the 13B engine with a Dynamic Effect intake system, Six Port induction and electronic fuel injection. Japanese customers could choose a turbocharged 12A version. It seems that management was wary about exporting this model just in case it gave problems. The reputation of the rotary for reliability and durability had been hard won over the previous decade and nobody wanted to risk squandering it.

When the P132 reached Australia we called it the Series Ill. The naturally aspirated 12A remained the sole engine, the car being offered with neither the injected 13B engine nor the turbocharged 12A. At least Australian buyers got the new option of power steering (standard on the Limited, introduced with Series 3), the 14 inch wheels and the significantly revised interior with three-spoke steering wheel in front of a new instrument panel and improved controls.

The RX-7 Limited was plush in a way that was at odds with its basic character. Two-tone paintwork, rather ritzy trim, electric windows and air-conditioning moved the car closer to the 280ZX/300ZX market. They also weighed it down. But the manual Limited (this time around the optional automatic transmission boasted an overdriven fourth ratio) was capable of running the standing 400 metres in 17 seconds flat - slower than the Mitsubishi Starion Turbo and the Alfa GTV6, but equal to the V6-powered 300ZX, which was an all­new design. The Limited was introduced with a pricetag of $23,120, which was cheaper than the last of the 280ZXs ($26,100) and almost a full five grand short of the 300ZX ($28,000). The Alfa GTV6 commanded $29,500 and the Starion around $24,000.

Quick as the RX-7 was, the chassis cried out for more power (although the appearance was still not looking too dated half a decade down the road). But Australian buyers would have to wait for the second generation car. Expectations would be high with the original having established itself as a modern classic within its own lifetime.

Years Available: 1979 to 1985 Engine: 12A (1146cc) twin rotor (2 x 573cc) Carby Transmission: 5 Speed Manual and optional 3 Speed Auto Power (Approx.): 103hp (77kw) (Series 1), 114hp (85 kw) (Series 2 & 3) Torque (Approx.): 108 Lb/Ft (147Nm) (Series 1), 113 Lb/Ft (152Nm) (Series 2 & 3) Weight (Approx.): 1060kg Chassis Prefix: SA22C Specification: Limited and Sports Original Cost (Approx): $14850 AUD (Series 1 price) rising to $23120 AUD (Series 3 Limited)

Great Cars of Mazda

Japan’s most powerful machine makes a spectacular debut

Launched in September 1971, the Mazda Savanna was powered by the 10A rotary engine and came in two body styles: coupe and sedan. Named after the world’s first steamboat and nuclear powered ship, the Savanna conjured up a powerful image of big game roaming across the wild beauty of the African plains. In its first month alone, the Savanna sold 5,406 units. This result, and the fact that more than half of the trade in vehicles in the first month were from other car makers, makes it no surprise that the Savanna went on to have such a huge impact on the market.

In 1972, the Mazda Savanna was updated with the powerful 12A rotary engine. This version repeatedly raced and eventually beat Nissan’s legendary Skyline GT-R, the undefeated Japanese touring car champion at the time. In 1976, the Savanna showed its dominance by achieving its 100th victory in Japanese motor sports — the record for a single model car — and became a firm favorite among the younger generation.

In a climate of growing concern over environmental regulations, the Savanna matched outstanding running performance with environmental compatibility. The Savanna AP was added to the series in 1973. Specially engineered to comply with the latest exhaust gas regulations, it used various means, including a thermal reactor* to reduce its emissions.

  • Thermal Reactor: A system by which NOx generation is suppressed due to the relatively low maximum combustion temperature of the rotary engine, while the high average combustion temperature is used to reburn hydrocarbons and carbon monoxide in the exhaust.

Early embodiment of Mazda’s sporting spirit

In March 1978, the Savanna RX-7 was launched as the successor to the Savanna series. Developed under Mazda’s “The pursuit of driving pleasure” slogan, the Savanna RX-7 had a low, sharp nose thanks to its front-midship engine layout, and a bold, wedge-shaped body that prioritized aerodynamics. A glass hatchback and other features also helped to earn it world-wide recognition. According to the late Paul Frere, a motoring journalist and then chairman of the World Press Association, “Its looks alone are cause for excitement. It’s refined, too. The handling can be summed up as simply marvellous.”

The Savanna RX-7 was highly active in motor sports in the US. Competing against the likes of the Nissan Fairlady 240Z and Porsche 911, the Savanna RX-7 left behind an unprecedented record of 100 victories in IMSA* series races.

The IMSA series was succeeded by the current Grand Am series. In the 2008 Grand Am series, victory in the first race, the Daytona 24-hour in January, went to the RX-8. That win marked a total of 22 class victories for the RX-8 at Daytona; proof that Mazda’s sporting spirit lives on.

  • International Motor Sports Association (USA)

<google uid="C01"></google>